1. Field of the Invention
The present invention relates to a disposable slide shipping and storage case for microscope slides and to a means for dispensing the slides from such a case.
2. Description of the Prior Art
Microscope slides are thin, elongated, rectangular plates of glass on which fluid, tissue smears, or other biological specimens are typically mounted for examination under a microscope. These slides are manufactured by the millions and are generally sold in conventional shipping and storage cases which are shallow cardboard boxes, in which the slides are placed on edge to form a horizontally extending stack filling the bottom tray of the box from front to back. In a conventional slide shipping and storage box of this type, the slides are oriented in a generally vertical disposition with the longitudinal side edge of each slide resting on the bottom of the tray. A close-fitting top fits snugly over the filled bottom box tray, and the box is sealed in a wrapper to prevent contamination during transit to the end user and during storage prior to use.
Due care is usually taken by the slide manufacturer in preparing and packaging the slides to prevent them from being exposed to dust, fungal and bacterial spores, and other contaminants during shipping and storage. However, once the box is opened at a laboratory site, removal of the slides by the end user is most often accomplished merely by grasping them and pulling them from the box. Also, the slides are normally used one at a time and the open box with the stack of slides in it is typically left on the table top until it is empty, thereby exposing the slides remaining in the box to the laboratory environment.
The conventional practice of leaving unused slides in an open box exposes them to contamination. For example, the slides in the open box are exposed to aerosol droplets from sprays used in the laboratory, to medical specimen fluids, and to various chemicals and liquids normally used in laboratories, such as fixative compounds sprayed on specimens being prepared on other slides nearby, disinfectants, water sprays, etc., as will as dust and other airborne materials. Furthermore, even though slides are normally handled by the edges, it is difficult to avoid leaving finger marks on the slides in the form of deposits of body oils and other substances carried on the fingers of the laboratory personnel.
Not only does such handling of the slides promote their contamination especially if the user's hand is not covered by a sterile glove--but it also subjects the laboratory personnel to the risk of cuts. Due to the presence of water droplets, moisture, disinfectants and other liquids in the laboratory, the slides will tend to stick together. In attempting to separate them a user's fingers can easily slip along the sharp edges of the glass slides when force is exerted to pull them apart. This often occurs when the slides contact moisture because the smooth glass surfaces in a stack of slides tend to adhere together. As a laboratory technologist attempts to separate the slides, accidental cuts to the skin can occur rather easily. Economy is a key factor in the manufacture of microscope slides. Therefore, the slide edges are normally not rounded or beveled, so that very little force is required to cause a finger cut. Needless to say, skin cuts are undesirable in the septic environment of medical laboratories as infection may readily occur.
Also, slides are normally grasped by the edges between a thumb and index finger placed against opposite edges of the slide to remove it from a box to mount a specimen, and to place the completed slide under a microscope. This technique is employed to minimize contamination. However, the practice of handling slides in this manner increases the likelihood of cuts by the edges of the slides.
Because economy of production has been so important, and since packaging of microscope slides in cardboard boxes has become so universal, little attention has been given to alternative forms of packaging and dispensing microscope slides. Nevertheless, there is a definite need for a system by which microscope slides may be dispensed as needed from a protected container in a manner which minimizes the possibility of cuts and contamination.
Efforts have been made to solve or at least minimize problems in handling microscope slides by providing microscope slide dispensers. Conventional dispensers which are commercially available eject slides one at a time from within a protected enclosure. One such conventional dispenser is illustrated in the 1997 Allegiance Scientific Catalog as Model number M6180. This device, which is made of sturdy sheet steel, has a rectangular container into which a vertical stack of microscope slides can be introduced through a removable side panel such that the lowermost slide in the stack rests upon the bottom of the container. An ejection mechanism is built into a bottom compartment of the container. The ejection mechanism is actuated by an external lever arm mounted on one side of the slide container. Manual rotation of the lever arm through an angle of approximately ninety degrees advances an ejector element under the lowermost slide in the stack. The ejector element has an upstanding lip which engages a rear edge of the lowermost slide and pushes the opposite end of the slide through a slot in the side of the container. The protruding end of the slide can then be manually grasped and the rest of the slide is then pulled from the dispenser. The next lowest slide then drops to the bottom into position for ejection when the lever is returned to its initial position.
While this conventional microscope slide dispenser works for its intended purpose, its design calls for rugged construction in order to withstand the repeated compression of an internal spring element. The device is therefore fabricated of steel. While durable and reliable, this device is expensive. Consequently, its use has been limited when compared with the extent of use of the typical process of removing slides by hand, one by one, from an open cardboard box. Moreover, the entire stack of slides still must initially be removed from its original cardboard box by hand and then hand loaded into the dispenser. Therefore, the risks of contamination and finger cuts still exist.
Another conventional microscope slide dispenser is sold as the Scienceware slide dispenser, model M6183-1. In this dispenser the lowermost slide in a stack rests upon a cylinder which can be turned by means of an external knob. This device ejects the lowermost slide sideways and edgewise from the stack through a slot in the housing containing the stack due to frictional force between the bottom slide and the rotating cylinder surface. This dispensing device has been found to be somewhat unreliable as the cylinder surface undergoes wear with use, which diminishes the friction exerted by the rotating cylinder. When worn, the cylinder tends to merely slip past the bottom slide in the stack. Also, this dispenser too must be hand loaded manually with slides taken from a factory package.
A need has existed for a simple, less expensive device in which microscope slides may be packaged, or into which they may be easily inserted, and from which they may be removed individually with minimized exposure to contamination of the slide surfaces and a smaller likelihood of finger cuts. In particular, a need has existed for a slide dispenser which is of sufficiently low cost so as to be suitable for use as the original factory packaging for the slides, thereby eliminating the need to transfer the slides to a separate dispenser at a laboratory or other end user location. Optimally, the slide dispenser should be sufficiently simple in design and low in cost so as to be discardable or recyclable after a single use. Factory packaged slides could then be dispensed one at a time for immediate use in the laboratory, with no intermediate handling or exposure of the slides to contamination.